Across the USA, this has been a summer straight out of a James Taylor song: We’ve seen fire, and we’ve seen rain. And we’ve seen sunny days that we thought would never end.

Wildfires out West. Record flooding in Greenbrier County, W.Va., in June, Ellicott City, Md., in July andBaton Rouge, La., in August. Endless sunshine in drought-stricken parts of Southern California.

We’ve also seen plenty of record heat, both at home and abroad. In July, Earth’s temperature, boosted by climate change and a fading El Niño, reached its highest point since instrumental record-keeping began 136 years ago. On Thursday, theNational Oceanic and Atmospheric Administration reported that the U.S. recorded hotter nights in June, July and August than in any summer since record-keeping began in 1895.

In the Arctic, summer ice has melted so much that the Crystal Serenity cruise ship is traversing the famed Northwest Passage on a 32-day trip from Seward, Alaska, to New York City. Melting ice sheets and expanding ocean waters are causing sea levels to rise, prompting more frequent “clear sky flooding” in Miami, Norfolk and other East Coast cities.

All of this provides further evidence, as if any were needed, that global warming is a here-and-now problem, not something to worry about in the distant future.

No, no single extreme weather event can be conclusively attributed to human-induced climate change. But this summer’s weather anomalies are entirely consistent with what scientists and computer models predict about a warming world.

The science of heavy rain events is straightforward: Warmer atmospheres and ocean surfaces produce more evaporation and more water vapor in the atmosphere to fuel rainstorms.

According to the National Climate Assessment, heavy rain events increased 71 percent in the northeast U.S. from 1958 to 2012. And, on Wednesday, a new federal report concluded that human-caused climate change played a “measurable” role in last month’s catastrophic flooding in Louisiana and increases the chances of such torrential downpours by at least 40 percent.

For the future of the world, the most significant news over Labor Day weekend wasn’t the latest on Hillary Clinton’s emails or Donald Trump’s visit to a black church. It was the agreement of President Obama and Chinese President Xi Jinping — leaders of the two leading emitting nations — to work together on December’s Paris accord to reduce greenhouse gases.

The initial round of Paris pledges won’t be nearly enough to meet the target of keeping the planet well below 3.6 degrees Fahrenheit of warming. But the pledges, if kept, might be enough to head off the most cataclysmic scenarios.

There’s plenty of room for debate on the best ways to adapt to climate change, mitigate its effects and curtail greenhouse-gas emissions. After another long, hot, soggy summer, however, neither Trump nor any other candidate for public office should be allowed to get away with the argument that climate change is a “hoax” or something not worth sweating over.